Microwave assisted alcoholysis of isocyanates derived from N α-(9-fluorenylmethyl)oxycarbonyl amino acids: Synthesis of N-Fmoc-N1-Z-/Boc-/Alloc-/Bsmoc-gem-diamines

A general and efficient method has been developed for the alcoholysis of isocyanates derived from the Nα-(9-fluorenylmethyl)oxy carbonyl amino acids with various alcohols including hindered ones assisted by MW irradiation. Thus, the synthesis of N, N1-diurethane protected gem-diamines wherein Fmoc protection on one of the amino groups and Z-/Boc-/Alloc or Bsmoc group on the other amino function has been accomplished. All the new orthogonally diurethane protected gem-diamines have been obtained as crystalline solid powders in 80 to 94% yield. The bisprotected gem-diamines have been fully characterized by IR, 1H NMR, 13C NMR as well as by mass spectrometry. © 2006 Springer Science+Business Media, Inc